\jP Biodiversity fe^HeriUge http://www.biodiversitylibrary.org Breviora. Cambridge, Mass., Museum of Comparative Zoology, Harvard University. http://www.biodiversitylibrary.org/bibliography/3989 no.1 21 -1 78 (1 960-1 962): http://www.biodiversitylibrary.org/item/2251 7 Page(s): Page 1 , Page 2, Page 3, Page 4, Page 5, Page 6, Page 7 Contributed by: Harvard University, MCZ, Ernst Mayr Library Sponsored by: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library Generated 15 December 2009 12:25 PM http://www.biodiversitylibrary.org/pdf2/001 74080002251 7 This page intentionally left blank. R V O R A Museum of Comparative Zoology Cambridge, ^Mass. Decembkr 20, XUMBER ]28 SIZE OF EXDOCEnOTD By Curt ^ AND BeRNHARD Kt^MMEL^ maximum size of fossil animal groups, whether mammals. reptiles, or invertebrates lias always l)eeii a fasciiiatiiig subject of inquiry, because phyletie size increase is one of the important trends that dominate the c^volution of living things. In the case of large animals, tlie evidence is often hard to assenil)le because their remains are difficadt to obtain, to transport, and to store. Squids are the largest living invertebrates and a ti*aditinn has been lianded down in paleontolos'ical literature that the largest fossil invertebrates likewise are to be found among the cephalo- pods, but few accurate data are to be found in published sources which are nOAV readily availal)le. Among the nautiloid cephalupods, it has long been suspected the Endoceratida furnished the real giants, but no accurate measurements in support of this statement are available. Clarke (1S97) stated that entire shells of Came voce ras pro- tciformc, 10 to 15 feet long (3 to 5 meters), had been found in the Lliddle Ordovician of IMinnesota. In the same publication, Clarke figured an internal cast of part of a siphnnele, from the base of the l)ody chamber to the adapical end of the spiess, which v/as 3 feet and 3 inclies long. Miller and Kununel (1944) described and illustrated additional species of these :\Iiddle Ordovician eucloeeroids from ]\riiinc.sota, which are deposited in the Carnegie Mnsenm. One of tlieir paratypes of Endoccras clarkei measured 750 mm loim-, is septate throughout and is not complete, adapically or adorally. The holotype of End<^rrras graciUimnm Miller and Kununel (1944) measured 670 mm in 1 Publication authonzea by the ]>irect(H'. V. S. G«M)l(»gical Survey -U. S. Geological Survey, Denver, Colo. 3 Museum of Comparative Zoology. 9 BREVrORA No. 128 leiig'tli, again an inrompli^te sptHMiiKai consisting' only of plirag- moeone. These same antliors deseribed a new species, Endoccras di covifhi nse, on two i)oi*ti()ns of llu? iiiteviial mold of tlie plirag- moeone from the Dc^corah formation, AVinneskiok County, Iowa. The larger portion is about G25 nini lonii' and the length of the smaller measures about 320 nun. Thev estimated the interval between the two pieces as about 115 mm, so the total length of this jjliragmocone was about 1,0G0 nnn. These authors also men- tioned that there is on display in the Chicago Natural History Museum a larger endoceroid that measures 6 feet in length. (1027) noted the occurrence, in Middle OrdoAucian limestones of Estonia, of endoceroids as nuicli as 5 meters long, but gave no further details. Flower (lOoT)) stated that specimens 12 feet in length had been collected and added that he was ^^not Avholly inclined to discredit a report of an (Midoceroid found in a quarry near AVatertoAvn, New York, Avhicli was measured before it was broken up and found to attain a length of 30 feet.^' As far as we have been able to ascertain, these somewhat vague statements are all that is presently available in the published rec- ord on the subject of the maximum size of endoceroid cep- halopods. It does not seem to be generally known that the ^Museum of Comparative Zoology at Harvard University possesses what ap- pears to be the largest fragment of an endoceroid cephalopod on display anywh(MT in the world. As Flowtn- (l!)o5) has stated, ''the removal of even reasonably complete si)(*cimens involves something very close to rpiarrying operations, storing them is anotlier problem." The specimen in the collections of the scum of Comparative Zoology is, therefore, probably uinrpie in museums of the world. The specimen measures 3,000 nmi in haigth but is not com- plete, adorally or adapically. In general the preservation is fair, but as a result of weathering and crushing the full diameter of the conch is preserved oidy in one plane, and in the other plane the onter shell is removed exposing traces of septa and in places the siphuncle. The first recognizable septa are 500 mm fi'om the adoral end but the whole specimen could well be phragmocone as this adoral 500 mm is slightly crushed and Mu weathered and one cannot tell Avhether septa are present oi )sent. The adoral diameter of the specimen is 280 mm. The eonch tapers at a uniform rate and the adapical diameter meas- ures 120 mm. SIZE OF EXDOCEROTD CEPIIALOPODS 3 Figure 1 — Large endoceroid on exliibit in the Mnseiim of Zoolo2*v. arative 4 BREVIORA No. 12S The 8i'i)ta slojx^ adapically at au anglo of about 45^^ and in the niid-pai*t of tho speeinion are spaced 17 to 20 mm apart. TJic sii)liunclc is visible oidy on the adapieal lialf of the specimen. About 1,000 mm fi-om tlie adoral end of the shell the siphuncle has a diameter of about 93 mm; at 1,750 nun from tlie adoral end of the sIk^II tlie sipliuuele has a <liameter of 75 mm. The first endocones appear 2,000 mm behind the adoral end of the slu_dl. Tlie spi(^ss UK^asurrs 510 mm in length. The surface of the shell bears faint annulations that are spaced approximately 10 to 12 mm ai)art. SUMMARY OF MEASUEEMENTS f « . • •••■■• Leugtli Adoral diaiiioter .... Diiuiieter ],000 luiu fruni adoral ciul.. Diameter 3,750 lum from adoral end .. Adapieal diameter . . . Diameter of sipluinele 1,000 mm from adoral end Diameter of six'^luincle 1,750 mm from adoral end . . Spiess lengtli . a • * * - -P * #■ B « « fl ff «■ ■ " « ■ 3,000 mm . , 280 mm « * * '* » * * » * t » m « * . . 220 mm . , .170 mm .120 mm ... 95 mm . . 75 mm .510 mm A graphical reeonstriietion of the shell on the basis of these measurements sliows that the entire fossil from its presently pre- served adoral end to the apex may have measured about mm. Tlie total h^ngth of tlie body eliamber is a matter of guesswork. There are few pul)lished and illustrated records of 'dny straight fossil cephalopod sliells, eumplete from apex to aperture, which are more than a foot or so long. In short shells the ratio of bod}^ chamber to phragmocone may he high, even larger than 1:1. + AVitli increasing total length of conch, however, ratio of body I'liamber to j^hragnuH'one is likely to decrease, although no defi- nite figures can ho stated. In a specimen of A('tf)iOceras hcloifensc (Foerste and Teichert, 1930, pL 28), which was 450 mm long, the ratio of body chamber to pliragmocone was about 1 :2. Leith (1912) described a specimen of Lamhcoccrus lam'bii (AVhiteaves) which Avas 45.5 in. (1,155 nun) long. He estimated the total length of the shell at 1,105 nun. The l)ody chamber was almost wholly pr(*served and not more than 250 mm long. Ratio of body chamber to ]>liragmocone was thus 1 :4.6 in this specimen. It sliould be noted, however, that both Actinoccras hdoitcnsc and Lamhcoccra^ lamlrii have body chambers with constricted SIZE OF ENDOCEROID C EPHALOPODS Q a|)(M*tureSj wliereas no eiidoeHn'oids with constricted apertures are known. It seems ph^'siologically plausible that in hirge straight ceplialopod shells the aniiiial should have a better )er with constricted apertnre than on one Avitli an nneonstrieted aperture; therefore, in shells which expanded uniformly from the apex to the aperture, like the enduceroids, the animal itself, and thus its body chamber, should have been relativclv larger. In a juvenile specimen of a straight ammonoid, Baculitcs ovatuSy Trueman (1911) determined the ratio of length of body chamber to phragmocone as 1 :0.7, but in adult shells this ratio becomes much smaller. If we assume the ratio of length of bodv chamber to phragmocone in endoceroids to be inore like that of Actinoceras heJoitoise we arrive at a length of the body chamber for the Harvard Endoccras of 2,650 mm and for the en- tire shell of 8,150 mm, or 28 feet. This is a conservative esti- mate, yet close to the possible maximum figure of 30 feet men- tioned bv Flower. Add to this the leng-tli of the tonacles ^Yliicli must have ex- tended a considerable distance in front of the aperture, cer- tainly no less than half the length of the l)ody chamber, and \ve have an invertel)rate animal considerably longer than 30 feet — a truly imposing size. Today's giant squid, ArcJiiteutlns, rivals and slishtlv exceeds in length the largest extinct endocer- oids. Spiirck (1028) records specimens of Arcliiiciithis dux fi-om the North Atlantic, Avashed ashore on the Norwegian Coast, that have body lengths of up to 2 meters and tentaeles as much as 10 meters long. The largest specimen to our knowledge is that of Archifeuthis Jutiueyi? recorded by Ycrrill (1870, ]>. 196) whicli measures 624 inches (17 meters). There is a model in the ]\Iusoum of Comparative Zoology of a specimen of Archi- Icitthts princcps, which was washed ashoi'c in Newfoundland, which measures about lo meters in length. More recently, Lane (1960, pp. 198-227) has critically reviewed a larger number of reports of finds of and <MU'(.)unters with giant squids. He is in- clined to believe that individuals of Arclnicnihh or some other o-enus, as vet undescribed, mav reach overall lengths of some 70 feet. While the Harvard specimen represents l)y far the largest nautiloid cephalopod on Avhich accurate data are now available, it is interesting to compare it with the largest anniionoid on record. This is Paclnjdiscus seppenradense Landois from the 6 BREVTORA No, 128 )per Cretaceous of western Gonnany (LandoiSj 189.1^ 1808). Ill 1895, Landois first described this fossil ammonoid whose shell was 1,800 iniii in diaim^ter and in which the last camera was 550 mm high. Landois^ reeonstrnetion provided the animal Avitli a body clianiber eqnivalent to only une-fourtli of a eouiidcte wliorl. From this lie conelnded that the total diameter of tho complete specimen uf his ammonoid had been about 2,550 mm. From later studies (Trncman, 1941) it is, however, likely that Landois' estimate of the length and bulk of living chamber Avas too low. If the body chaml)er of PacJnjrJIscus scppcDradense was eqnivalent, as is more likely, to three-fourths or one full volu- tion of the shell, the diameter of the adult shell of this ammonite would have lieen of the order of 3,500 mm, or more than 10 feet. A very approximate graphic plot of a shell of this kind shows that the total length of the shell of Pachyfliscus ^eppciirnrlrn^Cy when unrolled, would have been of the order ot 60 feet, or roughly twice as long as that of tiie largest endoceroid. r paper Landois (1898) attempted to estimate the weight of these giant cepludopods. On the basis of his estimated measurements he arriv(?d at a total weight of the ammonite as 1,455 ke:, or 750 k^ for the weight of the aniuuil itself, and 705 kg for the weight of the shell. AVe shall abstain from any attempt to iiielieate exact weights of the large emloceroids. The order of magnitude was almost certainlv the same as that inferred bv Landois for the giant V achy disc US y something of the order of 1 ton (about 1000 kg). It must be assumed tliat the weight of sliell and J Avhich for a h^nuth of i)\vY 5,000 mm was entirelv filled with calcareous di^posits, balanced tlu* buo^^ancy provided by the empty camerae and confined the animal to a strictly benthonic existence. Fmv, if any, fossil invertebrates ever surpassed them in bulk weight and size. One other point deserves attention : Phyletic size increase is a trend that as a rule continues until the end, or very close to the end of the evolutionary life of a particular group of organisms, as, for example, in the ammonoids. The endoceratids, however, reached their maximum size long before the time of extinction, in fact I'clativelv earlv in their evolution. In North America, as well as in northern Europe, endoceroid cephalopods survive to tlie end of the Ordovieian period, but reach their maximal size during ]\Iiddle Ordovieian time (Teichert, 1030, pp. 235-236). SIZE OF EXDOCEKOID CEPIIALOrODS 7 IiEFEUEXCES Clarke, J. M. 1S97. Tlie Lower Silurinii Ceplinlupodn of ^liiniesota. Geolot^y of Minnesota, vol. 3, pt, 2, Paleontology, pp. 761-812, pis. 47-60. Flower, li. II. 1955. Status of enJuceroid classification. Jour. Palcontoloj^y, vol 29, no. 3, pp. 329-371, FoKRSTE, A. F., and Teiciiert, Curt 1930. Tlic actinoceroids of east-central Xortli America. Denison Univ Bull., Sci. Lab. Jour., vol. 25, pp. 201-296, pis. 27-59. Landois, IL 1895. Die Riesenanimoniten von Seppenrade, Pachi/discu.^, Zittel, Sep- penradense II. Laiulois. Westfiil. Provinzial, Ver, Wiss. imd /r\ -^ Kunst. f. 1894/95, vol. 23, pp. 99-108, 2 pis. 1898. Gewichtsverhaltnisse der Eiesen-Amnioniten. Ihul., vol. 26, i>p. 27-28. Lane, F. W. 1957. Kingdom of the Octopus. Jarrulds, London. 2SG pp. Leitit, E. I. 1942. Xotes on tlie ceplialopod Lamhcoccras lamhil from Manitoba. Jour. Paleontology, vol. IG, no. 1, pp. 130-132, 1 text-fig,, pi. 22. .Miller, A. K., and Kummel, Berxtiard 1944. Some large straight Ordovician cephalopods from Minnesota Annals Carnegie Museum, vol. 30, pp. 19-38, 4 pis. Sparck, E AG mar 1928. Xordens Dyreverden. Ilenrik Kopi;)el, Copenhagen, 658 i^p. Teichert, Curt 1927. Der estlandische Glint. Xatur u. Museum, vol. 57, pp. 264 272, 7 figs. 1930. Biostratigraphie der Poramboniten. Xeues Jahrb. f. Mineral etc., Beil. Ed., Abt. B, pp. 177-246, 8 figs., 4 pis. Truemax, A. E. 1941. The ammonite body-chamber, with special reference to the liuovancv and mode of life of the living ammonite. Quart. Jour, Geol. Soe. London, vol. 9(^, pip. 339-378. Vi:rrill, a. E. 1879. The cephalopods of the northeastern coast of America. Trans. Conn. Acad. Sci., vol. 5, pp. 177-476, pis. 25-56.